1. Radboud university medical center, Radboud Institute for Health Sciences, Scientific Center for Quality of Healthcare (IQ healthcare), Nijmegen, The Netherlands
2. Mobile Doctors Service Foundation Haaglanden [Stichting Mobiele Artsen Service Haaglanden (SMASH)], The Hague, The Netherlands
3. Municipal Health Service Haaglanden [Gemeentelijke Gezondheidsdienst (GGD) Haaglanden], The Hague, The Netherlands